Ever know what an image looks like, but have no idea what its file name could be?
If you have a decent drawing hand on the computer, you might be in luck. There's a site called unofficial Google Image Search by Drawing, which literally lets you draw what you're looking for. Basically, you're just drawing a picture to upload to Google Images--but without needing to create it on your computer and then upload it to Google's search engine.
Upon loading the site, you'll see an empty box (this is where you'll draw), and a large color palette. Between the two is a small--and easily missed--sliding bar to adjust the thickness of the the pen instrument. There's no eraser tool, but you can either color over a mistake or use white to hide any mistakes. Once the search happens on Google Images, you can add keywords to better the chances of finding the right picture.
For this example, I drew a CNET logo but capitalized the "net" part to see if Google's Image search would still find it. And it did! So that proves you don't need to be exact in your drawings, just pretty darn close.
This Web tool can be a handy way of finding which logos look similar to your drawing, or even just for gathering design ideas in general. For instance, when if I draw a tomato it brings up a similar tomato, among other random red things.
You can also drag a photo from your computer to the input box on the Web site. After that, you can even make some adjustments by drawing on top of the photo before searching.
Finally, you can use an image from a Webcam. Instructions for this are provided on the page, and may slightly differ depending on brand and/or model.
Unfortunately, this search tool does not work with mobile devices at this time. The author of the page states that there is a bug on the Google Search by Image page that redirects mobile traffic from the results back to the Google homepage. Although the bug has been reported, there's no timeline for a fix.