There's a lot of focus right now on the bigger web portals enhancing their webmail product offerings and starting to monetise what were previously mainly free to use services e.g. Lycos, Hotmail and Yahoo! with their respective email offerings. 

Does anybody have any info on % uptake of the premium services from the free user base? And what elements are popular e.g. Mobile alerts, data storage, anti-spam etc And views on whether this is driven by customer demand or simply a desire to make some real money out of  their webmail services? I suspect it's the latter.

Also, can anybody help with how to justify within a business case the implementation of anti-spam (and anti-virus) solutions on a free-to-use webmail service - it's one of those intangible benefits that are hard to quantify.

Thanks

Nick