The web now turns into a giant washmachine for ideas and opinions. Information flows from many sources and every single social networker becomes an editor of his own choices, that others can decide to follow or not. This activity, as anything computer related, is intensively time consuming. So it involves to make decisions.
Time to Read
Using twitter for instance, or its kind of super artefact google+, will let you suffer from an avalanche of data. There will be new matter to discover at a rate that you would never have envisioned, as soon as you choose to follow many or some big sharers. So you have to decide to stop reading at some point in the day or week.
Time to Share
Then, you may decide to act as the editor I mentioned earlier, by choosing to reshare (retweet) some interesting posts and also maybe to share some original links that you will have found on the way. The whole system requires this sharing, and indeed this will ultimately attract a community of followers.
Of course a large part of one another's motivation in sharing or commenting other's posts is related to the desire of supporting ideas, or generously spreading information for a global benefit. Not interested in money in any way, even in the long term. However, even in that case you also must decide to stop sharing at some point.
Time to Create
If all this is not just a game, then you must reclaim your most thorough analyses. I mean that if you really wish to act as a provider of insightful comments and studies, then you should leverage that activity by uploading to your own site, then sharing. This will create more value from your keystrokes and thinking than simply trying to look good and advised on a comment board somewhere. You may decide so even if you have the best, non venal motivations. Also whether or not your main activity has to do with knowledge creation and dissemination
To put things straight a bit further, the information you release must be placed on a server that you control: you can access the files, and you can ultimately control the *.htacess* file. This means that whatever happens in the future, you should have the possibility to redirect the product of this activity to some other place, without loosing your search engine ranking.
Well, valuable creation should take the biggest part of it. Investing in a personal domain name, a personal web hosting, and a blogging/cms system may pay off in the future. Most certainely if you acquired some search engine visibility on a few keywords and you wish to leverage this visibility for a new activity someday. Reading and sharing certainely are not wasted time. But failing to create your own content surely is.