It's one of those ideas that never die - services to comment on sites have been around for more than a decade - I've seen a few during the dotcom boom. The problem always is lack of critical mass - the service user base is tiny compared to the vast amount of pages on the web. The chance of me finding and another user commenting on the same web page is tiny even if you have millions of users.
Consider making something sites can embed and make available to all their users instantly. For starters be THE service for a few sites instead of one of a dozen services for the whole internet. Something like a Disqus with drawing.
Also, no excuse in 2014 to use screenshots instead of the actual HTML of the site.
I was thinking of it as using it for fast communication with designor to illustrate small points but I would definitely like to explore the social aprt of it (seeing what others commented and os on). Great idea also on the embedding comment.
I went the screenshot way but, if I used html I think the only option would be to code the js as a bookmarklet. It is an interesting option btw.
You have to be sure to OMIT the http:// part for the site to work.
Also, on Chrome, dragging on the image frequently literally drags the image (rather than drawing). When the drawing does work, it happens about 2 inches to the right of where my cursor is actually placed.
Great idea and nice simple UI, this is literally the exact workflow I have for drawing my feedback on website proofs that I get from our designer, but I do it with a drawing tablet and MacPaint (I'm not that advanced). I'd really love something that let a designer just email me a link to a proof that I could annotate, and automatically send him my feedback. Right now the process is download-from-Google-Drive-and-open-in-MacPaint, draw-my-feedback, then export-as-image-and-put-back-on-Google-Drive.
I think the image generation is failing randomly. I uploaded a gif showing how I see the interaction. I 'all take a look at it and update it soon.
http://nimga.com/m/3FYRo.gif
Consider making something sites can embed and make available to all their users instantly. For starters be THE service for a few sites instead of one of a dozen services for the whole internet. Something like a Disqus with drawing.
Also, no excuse in 2014 to use screenshots instead of the actual HTML of the site.