Better Business Bureau gave them an "F" rating
http://www.bbb.org/arkansas/business-reviews/internet-services/gruddcom-in-fayetteville-ar-90256665They've had 3 complaints filed against them.
Now, if you look at their Woorank, that's not too hot either, meaning their website needs alot of work. I figure if their website needs the improvements that it needs, and they're supposed to be sending traffic to your site, wouldn't they want a better rank for their own site?
http://www.woorank.com/en/www/grudd.comTheir rank, based on trust, vendor reliability, privacy and child safety, highest rating is 71% which was child safety. I saw a few other complaints online that they say they'll send 55000 to your site for $5.95, $9.95 (the prices on the posts were different), but that they were billing $25 a month for you to be able to stay on their index of sites and if you complained about a "bait and switch" they would remove you from their index. So it seems there's some ambiguity in their product/pricing.
Traffic is one thing when you have a website, but don't you want the "right" traffic and not just someone who's clicking to click with no interest in your products or services? ROI is something to keep in mind. Another thing is bandwidth, although on Amazon you don't have to worry about that, but if you start getting alot of traffic from sources that really offer you no return on your investment and they start to eat up your bandwidth, etc that you're paying for, you're wasting your time and your money maintaining your internet presence for an audience that doesn't purchase your products.
That's just my humble opinion. Google, DuckDuckGo, Bing and search for more reliable sources of free advertising.
I know, personally, my presence on Facebook, Wordpress with my blog and Pinterest (all free), as well as my webstore, are my BEST sources of advertising, as well as reviews of products my customers have purchased and product testimonials, i.e., word of mouth advertising. I am a member of a dozen or so forums, help out there with questions and that too brings traffic to my site. I use Woopra ($4.95 a month and has live chat as a feature so if someone is online I can start a chat session with them and see every product/page they're viewing in live time) and I can see forums, backlinks, searches to threads and I know where my traffic is coming from and where my advertising dollars and time are worth being spent. Time is money, they say, and in my business they certainly are. From that information I work on my SEO, keywords, etc. (including misspellings) any search term used to find my website. Best money I've spent on my business besides the $19.95 a month for my actual cart/webstore.
Hope this helps, but I didn't seeing any rave reviews of this organization anywhere on the web.
This is my traffic for today only per Woopra:
