I bought a new domain the 11th of May. I build a website, and got it on air the 22th something in May with 2-3 backlinks just to activate SEs. In the first week of June, I started promoting it, and filling it with lots of content. Of course I expected the sandbox, and thought so it did. Since 4-5 june, I got first rankings in MSN because I edit some categories in nice linkpages. Even though I am corrupt as hell, so far I only placed it in relevant categories A while later I noticed also Yahoo has a sandbox. Then I started promoting it, its a SEO domain, with nice articles and content, and suddenly I got some PR5 relevant links to my domain. Today it appeared in the Google rankings on its nicest keyword as 42th result. Was the keyword not competing enough? I doubt it. Was the Sandbox not triggered here? I got lots of backlinks already. Over hundreds. Some single links on PR 5 pages. I did another domain that I actively January that kept until end of may before it was released out of the sandbox. What do you think? Not competiting enough?
In my experience, the sandbox is dependent on how competitive a keyword is. For example, if you have a unique company name that's also in the domain name, google will normally show your site in search results as soon as its cached, but only if the search term doesn't have any or at lest many results. There doesn't seem to be a sandbox if there's no competition, which would appear to be reasonable as the sandbox is IMO supposed to weed out fishy, short-lived affiliate sites that come and go and shouldn't be ranked high, but if the search term doesn't yet exist, your site is surely no affiliate site. For somewhat competitive keywords on my sites, I usually see these appearing in Google within about a month, while very competitive terms appear after 6 - 8 months. The sandbox effect also seems to be substantially attenuated by a listing in DMOZ.
When I search for it in Dutch, it has 351k results. Normally thats not much at all but remember, its just Dutch. Also some websites have it in their Title metatags, even some companies that have it in their front page metatags. Getting listed in the DMOZ takes longer than the sandbox