Mobile service Smub.it takes web addresses you put after its URL, like smub.it/http://lifehacker.com.au, and provides a grid of links to email, Twitter, Delicious bookmark, or otherwise share them from mobile phones and web browsers.
Ideally, Smub.it wants you to register and keep yourself logged in, so you don't have to enter your username and password credentials for any of the sharing services on its grid when you get there. And it's really made for the pre-copy/paste iPhone, smartphone, or tiny standard cell screen, where it's not so easy to copy, paste, or email a link you're visiting. The value lies in the URL usage, and, presumably, URLs you can remember and type rather than blog permalinks or search queries.
Still, if you're away from your convenient home or work computer and want to tag, share, or speak up about a web site, appending it to Smub.it might be a convenient option. Free to use, requires registration to bookmark and save sites and login credentials. Smub [ReadWriteWeb]