yaa it's possible and it's very impressive! i think it's gift for your site by Google..... i think SE wait for your post....good job
Not possible to a search engine to index a new post in 5 mins but yes it can be possible in 15-30 mins and its easy for the blog. Just ping your blog and inform google about your new post through google ping method. Its easy.
Yeah, it's normal, as Google likes fresh and unique content, whenever u had posted a new post at the same time, google bots were visiting your website, and they indexed that.
Nice, i need more traffic to my site (for free) i was wondering if anybody can help me? please pm me , thank you.