....post screenshots of your work! I think almost all who are interested in addons (especially on ace'd ones) want to see them on screens 1st, rather then to have install just to see what its look like! Like @ Curse-Gaming, every mod that has visual view has a picture on its page
I do agree with this motion... but don't forget that not ever mod has a visible effect, and most of the mods I've seen here are in a very volatile state. I'd suggest when a mod is at a release level then screenshots would be most useful. Before then, things are subject to change so much that the benefit of a screenshot for the beta releases would be outweighed by re-taking them every few hours of development.
A lot of Addons here are slash-command based, so it wouldn't exactly be very informative. We do however have descriptions and those serve just as well as pictures, it doesn't hurt anybody to read a bit. I think it's okay to expect pictures when an Addon has a GUI but with most of my Addons, like say ... Visor, Zoot, GoldenRun, DDR, Fireplace, VoodooVendor and so on and so on ... a screenshot would serve no purpose. In fact it would likely only serve to actually confuse a purpose.
"OMG, it adjusts the ChatFrame?!?"
"Err... no. It reactively casts spells to whispers, didn't you read the desc?"
"But you're showing the ChatFrame!!"
"I know ... that's because I was asked for a screenshot."
And so on ...
I think the only thing we really need is a NoGUI notification. Just to slap 'No GUI!' at the top of our posts or whatever if we're not providing a screenshot.
Just to stress, I agree that providing a screenshot is good if the Addon has a GUI (like I did with BugSack and Emo) but when it doesn't, a screenshot is pointless, no?