How is someone dominating top listings in Craigslist?

They have clearly optimized their ad content for their target keywords which can be duplicated by analyzing and reverse engineering their ad content. Then, just customize your ads using their strategy but conveying your company's edge in that niche.

Secondly, either match or outdo their daily posting frequency.

Finally, concerning the competitor flagging, even if they are leveraging auto-flagging software or paying to have it done manually, it's not possible to flag every single competitor. That means your best defense against that is to widely vary and diversify your ad content in terms of utilizing many different ad titles, ad text, images and even phone numbers. There is no way they can connect the dots to determine that all those different ad versions belong to you, the same company.

Flagging requires a concerted effort to accomplish involving a cluster of localized IPs and time and money. It's not as trivial as most people make it out to be to implement.

Hope that helps

Maybe because of 2 Reasons..

1) In overall searches results... They are posting all day and you will see their ads always on first results

2) If they are ranking on specific keywords, They are maintaining the keyword density in ads..

Follow the procedure and you will see your ads on first numbers as well:

Content - Use each keyword at-least once
Titles - Use exact match keyword in title
Images - Optimize image name, descriptions, title and author name.
Location - Add keyword in location if possible

Some sections allow you to add product name / type etc.. Add you product name with keyword.. I hope this will help...

Thanks,
Ahmed

I agree with all of the above, thanks guys BUT I know for a fact that some are using some specialized type of coding which keep them on top without posting multiple times each day.

Also, lets make clear a few points:

1. Coded ads are short-lived and don't provide any sustainability
2. Renewed ads that have proper keywords (age of ad) affects your algorithm rankings, along with body keywording (new in 2016, was previously limited to headline only)

I buy gift cards and at times I get relentlessly flagged by competition. Thankfully it just comes in occasional waves. When this happens, I will push together words that I know they are searching for and then after a day or two, I will go back and change it, so they are correct. I have found this to help keep my ads up during theses times. I think this has worked, because they seem to only searching for new ads to flag, with the assumption that they already flagged the older ones.