Yes I'm quite sure that folks will want RR Web service capability. In addition it would, I suspect, help the newcomers if you were to warn folks that there were frequencies that the scanner can't copy because the mode isn't supported. Here in the US, there's a rise in uses of modes such as NXDN, MotoTrbo and P25 conventional frequencies that this scanner can't handle. This is indicated in our database in the MODE column, and it's likely you would be able to query on it.
Here are a few examples...
This listing contains several P25 frequencies. (Keep in mind that anything in blue is a link)
Federal Scanner Frequencies and Radio Frequency Reference
See the Bentonville listing on this page - it uses 'DMR' instead of 'TRBO' in the mode field - but the idea is the same
Benton County, Arkansas (AR) Scanner Frequencies and Radio Frequency Reference
I can't put my finger on an example of NXDN frequencies at the moment but they'd be flagged with 'NXDN' in the mode column. I'm sure we have a few folks that can give you examples if / when you need them. The same could be said of D-Star amateur repeaters.
Telemetry ('Telm' in the mode column) would also not be receivable - see frequency 330.95 in this listing...
http://www.radioreference.com/apps/db/?aid=1113
These systems are not receivable by this scanner, but if someone were to install a discriminator tap, there is software that can do it. So you'd probably not want to block them outright, but certainly a warning is appropriate.
This one might be a long shot, but it's worth a try - there is a popular freeware program for the Uniden DMA scanners called FreeScan. In it's many options, it has a utility called 'EZ Grab' that allows a user to copy data from any site that has it set up as a table or columnar data. This would be handy for getting freqs from amateur radio sites, for example. We have a description in the FreeScan user guide here...
Freescan EZGrab - The RadioReference Wiki
I wouldn't pretend to speak for Assaf, but who knows, you might be able to get a copy of the code and install it. If not, well, nothing ventured, nothing gained, as they say. His FreeScan forum is here...
FreeSCAN
GL wth your program - from your screen shots it looks interesting for 125 owners...Mike