1) They pay out for the earned revenue within 45 days after the end of each month, if you have earned a minimum of $50.
2) The $25 sign up bonus is viewable in the section "My bucks".
3) You can place more than one WidgetBucks ad on your site.
4) According to their site WidgetBucks is compatible with all other ad systems including Google AdSense.
5) You can easily place the Widget Bucks ads code in blogs like Blogspot / Blogger and Typepad.
6) Impressions and clicks are updated each hour. The revenue reporting of the actual earnings is done up to 72 hours later.
7) The WidgetBucks code should be placed only on pages that have content primarily written in English.
Some new criticism here. I should mention that pages on WidgetBucks.com site are loading quite slowly. Also there are some pages that lead to loss of the user session in the browser so you must login again. Of course, these are not major drawbacks but they are still some issues needing improvement in the near future.
Another update with a dark and a light side:
First, I need to mention that there are some obscure things related to the referral program. One of them is that earnings of the referrals are not shown at all for a long period of time and it will be very good if they are visible (even with a delay of a day or two). Not showing referral stats for a whole month leads to suspicions at least.
Another thing related to the referral program (and I admit I cannot prove it) is that it seems the referral ID is lost when browsing between the pages of the site. So, if a new user is referred from your referral link and he/she decides first to browse through the site's pages awhile and after that goes to the signup page the ref ID is lost somewhere in the process.
Now, the new good thing I've noticed is that the WidgetBucks guys have made some improvements recently. The last one has been the faster loading widgets. We could consider this a good sign since it's not very likely for scammers to put efforts in such activities.
Here goes another update.
It seems that along with speeding up the loading of the widgets the WidgetBucks guys have removed the link pointing to their site from the widget's code - these are really good news.
And finally, I have written to them that it will be a very good improvement of functionality and trust in them if they make referral stats available in real time or at least to delay them only with a couple of days. They've answered that they'll put this on their "requested features" list. So, let's hope we will see the referral stats available soon without that month of delay.
There is still some more to be desired from the WidgetBucks program but I see some good changes are ongoing and now I can recommend this PPC program with a little more confidence.
A new update.
I have noticed that the problem with the user session lost while browsing the WidgetBucks site seems not present currently. I would suppose that it has been fixed.
Also it seems that the guys maintaining the site take the feedback from the publishers seriously and this is quite a good sign.