I have posted my poems on my website. For a long time, I have been doing this. Now, can I publish a book with the same poems which I had shared on the Internet.
If you self-publish, yeah, no issue.
Via a publisher? A bit trickier, especially if you don't take down the poems from your web site first. By putting your work on the internet you've already used your first publishing rights. This makes your work less attractive to potential publishers.