Google and the other search engines don't like it when you present different results to them versus real users.

This kind of spammy technique worked early on in the web but isn't something that's worked on a regular basis this century.

And even on the offchance it works for a while, it won't be long before the algorithm detects something is amiss and then you'll likely get hit with a penalty and not show up in the results at all.

Not worth the time and effort for the dubious short term gain.

using CSS is the easiest. but why bother? it will just make the site worse for Google.

cloaking or just make the text clear, but that's super easy to spot.....

As others have mentioned, you could probably do this the easiest using CSS. However, hiding text is frowned on upon search engines and it's a quick way to get your site hit with a penalty. I'd stay away from hiding text unless it something where registered members can see it, but guests/unregistered members cannot.

I want to use this on blogspot only, so short term can also ok but it is ok right now to use it on ?

As stated in the article you shared, doing this is seen as a violation of Google's guidelines and, might I add, a blackhat seo method which is definitely frowned upon.
Why do you want to do this anyway? Isn't the whole point of having a website making it visible to readers?

This is not a good SEO or it is against Google rules. You can block it by putting it in robots.txt.