If you are a heavy twitter use, possibly with more then one account, than I suggest you to give Tweetdeck a try. You can arrange, schedule, monitor and manage your tweets with ease.
Really great and free service where you can chat using a bunch of services like Skype or Google Talk within your web browser, meaning you don't need to install anything on your computer.
Let's create that simplified black and white effect on a photo using threshold adjustment and make a so called Internet meme or a motivational poster ready to be printed on an A4 size paper.
Google spreadsheets lets you create charts and graphs to visualize a data set. Let's take a look how to create a nice and simple chart in a matter of few clicks.