Why do my site's certain pages' SERP jump up and down like a yo yo almost every day (from page 1 to nowhere to be found, and it happens more than 5 times in a week), while other pages seem to be stable? And how long will it last?
It happens when your site is comparatively new. Keep adding content and keep building links at a consistent and steady rate. After a few months or so your position will become stable.
Your SERPS will change depending on alot of different factors. For example, I have dropped from my #1 spot twice today,and regained it twice. It depends on the sites that are competing, how often they update, and how interested the search engines are in those sites.
When your site is relatively new, yes SERPS change several times per day. It's a fairly long process (depends on how competitive your keywords are) before your position is stable. Keep building links and try to check results on a weekly/monthly basis instead of a daily or hourly one!
Thank you for the above answers. Anyway, why are there a few pages of my site which remain in the stable position and NEVER change their SERP compared to others which change their SERP more often?
The SERPS are CONSTANTLY changing... because Google is constantly crawling and indexing the web. New URLs competing for the same keyword phrases, new links being discovered or dropped pointing to old URLs that rank for the keyword, etc. cause rankings to change as they continually crawl and index the web. Sites like Digital Point are being crawled 24x7. The search engines don't publish a new index every X days or months. Their indexes (and therefore rankings) are being updated minute by minute and therefore rankings change minute by minute. How do you think that THIS post can get into the SERPs within minutes of being posted? However if you have an old URL that is jumping around a lot it's likely because it doesn't have a strong backlink profile. If it had lots of good backlinks then its rankings would likely remain stable. But if it doesn't then your LOW ranking is likely where it "should" rank legitimately, and they are just throwing you a bone every now and then by including your page in the first page of the SERPs to see if it DID actually rank there whether users might consider it useful or relevant to their search phrase based on click-thru-rates and bounce-back rates. If it's a brand new URL that shows on page 1 for a few days or maybe even a week or two and then disappears then it is likely the Google Honeymoon. Google frequently shows new sites/new URLs on page 1 even though they shouldn't legitimately rank on page 1. After a brief amount of time there, the URL then falls back into the SERPS where they "should" have really ranked all along.
Everything above is correct, and I just want to point out that patience is key You should REALLY worry when you can't find your site at all when you do a domain search.
They may just be sitting in the right place. By this I mean that there may be a big difference between the authoriti of those above you, and those underneath you. If you wanted to increase these pages rankings, start linking them in any articles that you publish off site, and use the right keywords in anchor text as well. That will definitely help. Remember to use Pingler on those pages as well when thye have been updated. Keyword relevancy on page also helps a hell of alot
I have seen serp's change everyday also, its just a fact about google's relevancy ranking algorithm - remember google wants to deliver the most relevant result possible - so it keeps thinking some other is page is most relevant at one time, then your page also appears. It is just part of a dance.
All the answers specified in this thread are very correct, additionally as per my observation, It depends on the from which data center the query is served. It takes some times to sync all data centers of google.