That said, if it's reading other people's blogs in order to write an interesting blog yourself, you can start today.
Literal
However, interesting blog [object-を] write for-the-sake-of, people [genitive-の] blog [object-を] read [if-the-case-のなら] today from-can-do.
A casual reflection about blogging habits. The discourse marker ただ at the start functions as a soft 'but,' 'however,' 'that said' — marking a qualification to something previously discussed. ~のなら is the conditional of supposition ('if it's the case that X') — similar to ~なら but with the explicit nominalizer の, making 'the situation in which X' the condition. 今日から出来る ('can do from today') uses から to mark the starting time — Japanese often uses から this way for 'starting from X' in schedule/plan contexts.