Hosting Detexify costs money and if it helps you may consider helping to pay the hosting bill.
Anyone who works with LaTeX knows how time-consuming it can be to find a symbol in symbols-a4.pdf that you just can't memorize. Detexify is an attempt to simplify this search.
Just draw the symbol you are looking for into the square area above and look what happens!
The symbol may not be trained enough
or it is not yet in the list of supported symbols.
In the first case you can do the training yourself.
In the second case just drop me a line (email@example.com)!
I am rewriting parts right now an training isn't functional in this version.
Hosting of detexify costs some money. If Detexify helps you, you might want to help cover these costs. The backend where all the computation is done is running on a server that is sponsored by my former employer Zweitag GmbH but the frontend and database are hosted separately and still need to be payed for.
No. Have a look at http://shapecatcher.com for Unicode.
Philipp Kühl had the initial idea and Daniel Kirsch made it happen.