They tell you how many times you've asked, edited, answered, organized, flagged, and other thing you can do here on WikiAnswers. To see how many you have in each division, click your username at the top of the blue sidebar on the left of the page.
No, recommending a question or a user does not give you contribution points.
Historical contribution points were introduced on Mon Feb 01, 2010, when the Split Contributions feature went live on WikiAnswers.
Your total WikiAnswers contribution points are calculated as the sum of all of the contribution points you have earned. These include first answers, edits, organizational actions, questions asked, and community contributions. All of these points come under the heading of "Contributions" in your WikiAnswers profile. Trust points are slightly different. Contributors do not directly earn these points through their contributions; they are awarded trust points by other WikiAnswers users. Therefore, trust points are not counted as contributions, and do not add to the contribution points total in a WikiAnswers profile.
Contribution points are simply an indication of how active a user is. Some people contribute to this site much more than others. Every time you answer, edit or comment on a question, it counts as a contribution point. If you click your username (top left of the screen) it will show a summary of your contributions. Trust points are a different subject. Trust points are awarded by people who found your contribution useful, informative or positive (and sometimes amusing !) - Trust points are not an indication of a contributors qualifications though.
Break even point = Fixed Cost / Contribution margin
You get one contribution point for answering a question, as it is only one action.
When re-categorizing a question 1 category equals 1 contribution point.
Asking a question is one contribution point. Each category it goes in is also one contribution point. 1 question (1 point) + 1 category (1 point) = 2 contribution points for asking a question and placing it into one category. Since the maximum number of categories a question can be placed into is 3, the maximum number of contribution points a user receives for asking any new question is 4 points: 1 question (1 point) + 3 categories (1 point for each category x 3 categories) = 4 contribution points for asking a question and correctly placing it into 3 categories.
Yes, you get one contribution point per answer.
Giving a Trust Point does not make any significant contribution to the site, as giving an answer or editing a question does. If that were the case, members could easily give out Trust Points to gain contribution points, which defeats the whole object.
Both Contribution and Trust Points are very valuable for easily seeing which members of the community are more experienced and trusted. It is also a nice way to award those that contribute to the site with various badges and awards for reaching certain levels.
Any action you perform on WikiAnswers will generate a contribution of some kind. Whether the activity generates one or more points depends on the activity. Chatting, forum entries, and merging may not generate actual points, and the totals of your points could be adjusted by future guidelines. The point of wikianswers is not simply to generate points, although the points indicate your comparative interest and aid to the site.