Start-up's marketing, Twitter helps !

I suppose it would be very nice to have full pockets to have resources for marketing and brand awareness, but being a technology "bootstrapping" start-up, resources are very limited :-)
We have to decide each brand/marketing action valuable to spend our restricted marketing budget, and our own time.
We learnt about social networks by doing, and started with Twitter shyly and being a bit skeptical, but now, our first tweet was written 18 months ago.
Today, we read in a Nurun (a global presence marketing & communication company) report (report available in spanish) that Solaiemes is the 4th spanish most "conversational" brand in Twitter. Of course we are not leading by number of followers (about 300, more or less as following but not symetrica at all) or number of tweets, mere activity, we are happy because we are well positioned just where we need, conversation.
We used Twitter to announce products, our blog posts, our slideshare keynotes, and try to generate debates. We could create conversation with analysts, other start-up's, potential partners and costumers, communication managers of very nice companies able to provide feedback, where we suppose cold door email will never work, it seems tweeter is not a cold door if used properly, with non invasive style.
Of course we are aware that we should keep posting, creating presentations to share producs ot views, shooting video-demos of our portfolio, being at Facebook & Linkedin and of course, we need to update the website (be patient), but...Twitter becomes the circle around the communication strategy, and we recommend start-up's to use it, learning slowly but avoiding the risk of being considered spammer, or just 1 way emitter and use it to announce new info available in the other social or corporate communications channels.

Thanks Twitter for your help and thanks Nurun to just seeing us in the middle of so many brands using Twitter.