The first action you need to do within this next 7 days is slog your mind off creating a technical blog and associated web sites. Perhaps, even LinkedIn, tweeter and Facebook accounts that is not used for documenting frivolous activities.
In these technical sites you write comprehensively using your technical knowledge. Not necessarily complete, but a continuous WIP (work-in-progress). A separate site ("site" as in Google-Sites site), for example a site each on Qt/C++, JavaEE, Operations Research, etc.
If your profession is associated with software, you should also maintain/contribute to some Google Code or open-source projects.
Every time you add new items to a site, or modify and existing page, or started/ended a significant contribution to an oper-source project, your blog would have an entry describing the update.
Your blog would be used to write a descriptive summary of the update. And following posting a summary in your blog, you would tweet it.
For the particular Facebook/Google+ account
- Family vacations are OK. (Indicates you have a life)
- Formal company and social functions are OK (indicates you have a network)
- Alcohol and pot binges not OK.
- Criticism of colleagues and public/political figures not OK.
- Religious/political opinion not OK, but biblical/quranic/mahabharata exegesis OK.
Then to the companies which you are rejecting their offers, there is no angst necessary in politely telling them that
You did not have an easy time deciding but that you have found a company most in-tune with your current direction in life. You let them you feel you could still contribute to society at large and is keeping a blog that will have very useful professional information.
Then tell each of the companies
I would like to keep in touch with you socially. You should follow me in my LinkedIn account (where I document the progress of my professional life). I also have a few technical web sites (list the sites each with a short description). You should follow my progress in my blog (name the blog) and my tweeter account. Feel free to comment on my blogs or ask any questions there.
Thank them for the opportunity they had given you.