It's not a very big pain point. If I want to share links with friends, I tweet at them or send a DM, or use an IM client. So I would only need this app when sending a link to a friend that's not on Twitter or IM, which is like once a week. Not a big enough need to install a bookmarklet.

That said, it does appear pretty well done. I would consider taking the code and pivoting to an adjacent concept - one that you've validated and proved product-market fit.

http://www.ashmaurya.com/2009/11/achievingproductmarketfit/

http://blog.clarity.fm/the-journey-to-product-market-fit/

http://www.slideshare.net/ashmaurya/10-steps-to-productmarke...

good luck