Facebook, a survey

Facebook (unless you pay to "promote" an item) only shows your posts to a certain proportion of your friends, (even if they're using the "most recent" way of looking at updates). In a flawed attempt to harness the wisdom of crowds:

Poll #13209

Open to: Registered Users, detailed results viewable to: All, participants: 14

View Respondents

What percentage of your Facebook friends (of the ones who look at Facebook in the hour or so after you post) do you think are shown what you have written?

View Answers
Mean: 39.29 Median: 30 Std. Dev 24.92

No-one 0		0 (0.0%)
10		2 (14.3%)
20		3 (21.4%)
30		4 (28.6%)
40		0 (0.0%)
50		1 (7.1%)
60		1 (7.1%)
70		0 (0.0%)
80		3 (21.4%)
90		0 (0.0%)
Everyone 100		0 (0.0%)

Assume that this is a plain old text update, not a photo or anything like that. Friends that have interacted with you more often in the past will tend to be shown your activity with higher probabbility. If you have no Facebook account, don't complete the poll ;)

There is no right answer that I know of, though if someone has hard data on how to calculate these things, do comment with links.

Follow-up additional poll

Poll #13210

Open to: Registered Users, detailed results viewable to: All, participants: 21

View Respondents

Furthermore:

View Answers

I assume that people who don't get shown my updates are the ones that actually weren't interested
1 (4.8%)

I think most of the people who don't see my posts assume it's because I haven't posted
14 (66.7%)

This misconception has caused problems at least once
3 (14.3%)

I have paid Facebook to promote a post at least once
0 (0.0%)

I don't have a Facebook account, but I used to.
1 (4.8%)

I have never had a Facebook account.
5 (23.8%)

[Like]
5 (23.8%)

ETA: I'd be interested to hear what the problems caused by the misconceptions were.