Last week Martin from Evlaa.com explained the Evlaa Lightroom plugin that allows you to create a private collection of images in Lightroom that your client can review, rate and comment on from a SmartPhone, tablet or computer. This plugin streamlines the process of having your client review images.
While many real estate photographers probably don't put a lot of energy into client review, there are some that could make use of this functionality.
I tried it out. It works quite well. Anyone can try it out, free for 15 days. After that it's quite reasonable (54€/year or 6€/month). If you need help getting going there are a bunch of good tutorials one their support page.
Check it out and give it a try.