No it is not true!

Especially with geo focused results, country specific extentions should be the first choice.

Example .ca for canadian or .co.uk for UK based websites.

Also think about some of the strongest sites like wikipedia which is .org and other edu or .gov sites that dominate SERPs.

There is of course a high correlation between high rankings and .com domains - but most likely due to age and optimization. 10 years ago you probably would have registered a .com and now that short keyword rich domain has age and has probably collected a lot of backlinks and added a lot of content, making the site strong today.

In saying that I would still recommend a .com because people and browsers typically assume its a .com first - but it shouldn't be your only option. Use the extention that best fits your geo target and organization.

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