- Generated 400+ signups to receive the 299 Steps to Website Heaven ebook for free on August 1st - f
rom which I received 17 service enquiries, and 4 turned into business worth over £4500 (yearly contract value)
- Generated 50 downloads of a free Google Adwords ebook (today alone) -
an affiliate link in there seems to have earned me £75
- Gained 2 new customers for my higher Google listings service -
worth over £1800 over the year
- Gained feedback on 2 new business ideas (an online course and a day by day blog featuring the optimisation of a website) -
can't put afigure on this but it's valuable to me
- Followed a link to get free promotional magnets for my company -
saved me about £50 probably
- Found out about 2 web conferences I wouldn’t have known about otherwise -
free conferences that saved me money on training
- Promoted a client’s article, which was then picked up by StumbledUpon and received over 400 visitors -
client goodwill - priceless 
- Been offered a column in a holiday industry related magazine - worth over £4k over 12 months
- Had industry news come to me, instead of me having to go out and find it -
time saving
So, if I take the yearly values and split them into monthly values, I reckon that week made me at least £850 for the month of July. (Bear in mind it was the first week I had tracked business through Twitter). Plus the affiliate money and the saving on the magnets. I won't quantify the savings on training as there's every chance I woudln't have paid for it anyway
£850 + for 3 and a half hours work (which was more like play really AND which I did while doing other work too) - £200+ per hour - I'll take that and party
Of course, the real value will become known when i have tracked sales and leads from Twitter vs other sources for more than a week - I intend to do a 3 month analysis.
As for how long did it take to learn? I'm still learning, as we all should be - it doesn't take long to get the hang of twitter, but it's still a test and measure form of marketing, like any other.
Hope that helps
[edited to add that another 2 contracts came in that I can attribute to that week too - worth low thousands over the year]