The online nature of Twitter means that it’s highly unlikely you know the physical addresses of many of the people you follow, which if you want to send them something in the real world, could be problematic.

Whether it’s a Twitter buddy’s birthday, someone’s a little under the weather, you want to say thank you, or just be awesome, there are a variety of services out there that can help you out in such a situation.

We’ve pulled together a list of five websites that, utilizing just a Twitter handle and a credit card, will have actual gifts winging their way in the real world to your online friend in no time at all.

1. ParcelGenie

Perhaps aimed at the younger Twitter user, ParcelGenie offers affordable gifts across the categories of “fun,” “flirty,” “cheeky,” “cult” and “celebratory” with Love Hearts and strawberry lip gloss the current most popular items while we were visiting. Basically, if you’re looking to send a Twitter contact a Whoopee cushion, or a badge that reads “boob inspector” then this is your new go-to place.

Once you’ve signed in via oAuth, the site auto-selects a gift and someone from your followers to send it to as a kind of demo. This is unnerving at best, and frankly terrifying at worst as you sit petrified, scared to move the mouse as the site lines up “After Dinner Willies” for your boss, complete with an auto-generated message. Obviously you have to actually add the item to your cart before anything really happens, but it’s a point worth noting for the faint of heart.

On the practical side of things, you can only send gifts to people that are following you. Once you have selected an item and a recipient, you choose whether you want the gift to be public, private or anonymous, after which ParcelGenie messages the giftee asking for an address and, assuming your buddy provides the requisite info, the parcel is then sent.

Delivers To: The U.S., Canada, UK, Australia, plus some European countries

Gifts Available: Keyrings, badges, candy, drinks, mugs, magnets, various other low value items

2. Tigerbow

This good-looking site offers a more grown-up selection of giftery with books and movies catering to any get-well soon scenario, flowers and food great for thank yous, and comedy tees. There’s also a card-sending service which is available worldwide (unlike the gifting that’s currently U.S.-only), with the nifty option to design your own.

Once you’ve registered, verified your email and selected your gift, it’s just a matter of signing in to Twitter, selecting a contact from the list and then adding a Twitter message (there’s a separate option later in the checkout process to add a message to go with the actual gift). At this stage you can chose whether you want the recipient to be able to see the gift they are getting, or keeping it a surprise.

The giftee then gets a message from Tigerbow, can view your message on the site and then decide whether they want to accept, and if so, where they want the parcel sent. If the recipient refuses the present, then you won’t be charged and at no point is any address info shared.

Delivers To: The U.S. only for gifts, cards worldwide

Gifts Available: Flowers, cards, foodie items, t-shirts, books, movies

3. Twitgift

Twitgift currently offers a very limited selection of items made up of mostly cookies and a few geek-themed phone cases and jewelry. However, the site is actively looking for suppliers with “interesting, unique or tasty” products, and is supposedly making plans for expansion to other countries, so it’s definitely worth bookmarking.

Boasting a super-simple user experience, you simply sign in via oAuth with your Twitter account, select the gift you want to send, enter the Twitter name of who you’re sending it to and enter payment info.

The recipient then gets a tweet that is customizable, but along the lines of: “I just bought you a @twitgift! Claim your @twitgift at” The recipient can then visit Twitgift to add their shipping details (at which point the service tweets you to let you know the gift has been accepted). Alternatively, if the gift is not claimed in a week, the order is canceled and nothing is charged to your card.

It’s worth noting that unlike other services, the @mention nature of the notification means you can use Twitgift to send gifts to people who don’t follow you.

Delivers To: The U.S. only

Gifts Available: Cookies, phone cases, jewelry

4. Twegistry

Once you’ve oAuthed the sign-in on Twegistry, you can browse the online present selection which includes some nice gifty bits as well as some sexy underwear – so, clearly ideal for the stalker market.

Simply enter your recipient’s Twitter name and select the gift (prices include both shipping and taxes) and then checkout via PayPal.

Twegistry will then send a message containing an @mention to the person you’re sending the present to with a link so that they can either accept or decline. Like Twitgift, the way this system is set up means the person you want to send something to does not need to follow you back in order to generate the message.

If they do decline, then your purchase will be refunded, otherwise the gift will be sent off to them pronto.

Delivers To: The U.S. only

Gifts Available: Flowers, candy, cakes, teddy bears, saucy undies

5. SendSocial

In addition to being UK-only at this stage, SendSocial works on a different principle than the services outlined above as it does not restrict your choice of gift. It’s more a social delivery service that will help you send anything to a Twitter user.

Just sign in with your Twitter ID via oAuth, enter your name, email and address info (and go through the email verification process) and select the Twitter name of the person you want to send something to.

The service then generates a tweet along the following lines “@[recipient] I would like to send you [item], via SendSocial. To accept, go to[unique link]” Once the receivee accepts and enters their address, SendSocial creates a barcoded address label (so the actual location is not revealed at any stage) for you to print out, stick to your parcel and wait for the courier to collect.

Pricing is worked out on a weight basis, with anything up to 2kg costing just £3.99 (around $6) to send and the service takes between three to five days once the parcel has been collected.

Delivers To: UK only

Gifts Available: None – send your own

For more social media coverage, follow Mashable Social Media on Twitter or become a fan on Facebook

More Twitter resources from Mashable:

5 Free Services for Pre-Scheduling Your Twitter Updates

What Twitter’
s New Ad Model Could Mean for Small Business

10 Dos and Don’ts for Brands on Twitter

HOW TO: Spring Clean Your Twitter Account

4 Tips for Tapping Into Twitter Conversations

Image courtesy of iStockphoto, fotosipsak

Reviews: Australia, Facebook, Twegistry, Twitter, iStockphoto

Tags: parcelgenie, sendsocial, tigerbow, twegister, twitgift, twitter