Google Pagerank 4 for my website!!!

Hahaha..... just noticed my website has a Google Pagerank 4 today!!!
Hooray!!!!
Never expect that they will upgrade my website rank, given that it is very hard for a website to upgrade to Pagerank 4 and above, according to the SEO experts.
The last Pagerank 3 (and first time) was given in 25 October 2006. It was quite a shame, since I didn't update my website since then. Thought they will rank down my website pretty soon, but in fact not. The only reason I can think of is that more visitors come to my blog as my web presence is getting better on search engines.
Not only the main page rank was upgraded, the rest of the pages also upgraded by 1 grade each.
Hmmmm..... think I must do something to it to boost it up a bit, though I am dead busy in updating my blog daily.
Oh ya, got to put up the 3d caricature dolly into the product page, which has been delayed for more than 1 week. Don't know whether I have the time this weekend, given that that FIR singer Ah Qin will be coming to my gallery for a live sketching tomorrow at 2pm, which should take up at least a few hours, plus I will be going to the PC Show at Suntec City after that. Shopping time again. Looks like I am finally responding to the Great Singapore Sales (GSS) finally. Hahaha.......