Integrating user comments with web-map?

Here is a strategy from Mapbox which uses Google Docs and Google Forms, which might help:

someone ... fills out information about it into a web form. The data is then stored in a Google Doc spreadsheet. We use the Google Spreadsheet Data API and the MapBox JavaScript API to plot the reports on a custom MapBox map as part of a live visualization. When new reports come in, they show up on the map immediately.

The use of Google Docs (instead of PostGIS) might help to make the "additional comments and interactions" bit easier, eg if you made the document editable by registered users, etc.

Here is a good idea that was implemented 2 years ago.

Ben Marsh created the #UKsnow map - where for a datasource users tweeted the snow factor (0 to 10 on the amount of snow falling) - and town name or UK postcode, he would use the twitter api and geocode the position.

http://uksnowmap.com/#/

but only really comes into action for 3-4 days (if any) a year when the UK gets wet snow.

There are a few ways that come to mind. You could use the OpenGeo SKD suite or GeoNode and then create a custom openlayers/SDK map that allows users to draw points and add attributes to the points, in your case one attribute would be 'description'.

Or you could create a CartoDB table, again with an attribute 'description' you could then make a map of the CartoDB data using leaflet, openlayers or google maps api. Then with a bit of JavaScript write up a form that creates a REST POST to the Cartodb table.

Maybe an even more simple (but defiantly more limited) option would be to create a Google fusion table, render some points to a google map. Then create a google form that creates a new recored in the table for each form entry.