if by "here" you mean this forum: points are only for showing off; no value whatsoever
if by "here" you mean the Marriott Rewards homepage/account: there are lots of things to do with your points:
* "free" nights (points anywhere from 10.000 to100.000 per night)
* shopping for items (I recently bought some gift certificates; since I am not American, the best conversion rate I could get was about 350 points for 1 euro if I remember correctly)
* upgrades, etc.
search the forum for more info :-)
Marriott Rewards Insider credits have nothing to do with the Marriott Reward points. Insider credits illustrate your participation here, Marriott Reward points are the stuff you need to redeem for free nights.
A common error made by newbs on joining Marriott Rewards, or any of the major hotel schemes is booking to stay at the hotels via an online agent such as Expedia. None of the major schemes give points when a guest books via an online travel agent like that. Regrettably only reservations made via Marriott.com, the Marriott phone line or your employers appointed travel agent (but not always) qualify to receive Marriott points and night credits.
US/Canadian stays usually credit to your account a day or 2 after checkout, internationals may take a week. If over 2 weeks have passed raise a missing stay enquiry on Marriott.com. And watch out for point-shorting, it's a real problem around here, especially internationals, 3 of my last 6 stays were dramatically point-shorted and someone posted earlier today that they were awarded only 59 points for a paid stay at the UK Leicester Marriott, indicating a rate for the night of only $5:90!!! You'll need to call Marriott if you find your points shorted as its more complex to resolve.
Although there are irritations, if you travel regularly and like Marriotts the program is really worthwhile. Since joining in 2005 I've stayed about 450 paid nights and redeemed about 120 free nights and 2 first class return transatlantic flights. And made some great friends on this forum, and that last bit is priceless!
As ramoneur rightly says, credits on this forum have no value, other than bragging rights.
Points for stays usually show in your Marriott Rewards accounts within a couple of days. If you have not received them after 10 days, contact the hotel direct, or fill in a missing stay form on Marriotts Rewards.
There is a lot about missing stays on this forum. Just use the search box at the top of this page.