Web means the game can be played through the web browser. It’s annoying when I click on the Web link, I get a download page (I was expecting a web game). So please label your links appropriately.
Here are some cases:
http://www.ludumdare.com/compo/ludum-dare-29/?action=preview&uid=34696
http://www.ludumdare.com/compo/ludum-dare-29/?action=preview&uid=33937
It’s also nice if you include the tech you used for the web game. Ex: Web(Flash), Web(Unity), Web(WebGL) so those without required plugins won’t waste time staring at a blank page wondering if the game is loading.