Whilst I'm not the OP, I am in the market for something like this, hence being in this thread.

# It's slow, each page load and column sort is 1.7+ seconds.

# It only sorts in increasing order, not decreasing, and if you'd want only one direction you'd likely want decreasing for followers and Alexa rank.

# Categories (Regions, and Platforms) should be faceted, to keep the UI tight consider the pattern employed by Excel for picking column filters.

# URL and Twitter should be sortable.

# Whole and filtered lists should be exportable to CSV.

Whilst these are all UX related, the last one for content.

# Add a "Type" column, this could differentiate between the type of site: "News", "Directory", etc.

This is all possible with a sprinkling of JS, no need for heavy server-side stuff :-)

I hope my partially unsolicited feedback is useful, have a great day.