Linky facilitates the process of posting links to anything you want to share via Facebook, Twitter, or App.net, so you can get things out quickly. When you use the app's built-in browser, you'll have immediate access to sharing tools and a streamlined sharing process that makes everything more convenient.
Simultaneous posting: You can post to two accounts simultaneously through this app. Just add the accounts you want to use, and choose which to send the post to.
Streamlined process: Thanks to its built-in browser, this app lets you browse and post directly. And you can enable Linky as an option in Safari and other apps to post directly from them as well. When you find something you want to share, the software will automatically generate a post for you with a headline or the title of the page, with the link included. You can edit the contents as you see fit, or just hit Send to get the message out.
Limited integration: Unfortunately, this app only lets you share on the three sites mentioned above, and it limits you to two simultaneous posts at a time. Especially since there are only three options for posting to begin with, it seems strange that you can't use all of them at once, and it would be much more useful if posting to these sites was supported as well.
Linky is a great tool, especially if you frequently share links via Twitter, Facebook, and App.net. The limit or two simultaneous posts could be frustrating for some, but most people will probably be satisfied with just Twitter and Facebook anyway.