All these job titles will vary from company to company - bearing in mind that any company can call anyone anything to make them sound good (I remember a lot of "Junior Vice President of Marketing" and that sort of thing during the dotcom boom!)
However as best I would say this is what they would mean to me.
1) Communication Strategists - This would probably be a higher up role that would work out strategies for how an organisation communicates with it's customers, through marketing, PR, sales etc. Basically they would be trying to keep communication consistant and in line with brand values, rather than working the details themselves.
2) Advertising Account Executives - A salesperson selling advertising of one form or another.
3) Media Liason Officer - The person who answers calls from the press about whatever. Normally only hired by large companies. Often hired by companies that get critisised a lot or who are in the middle of takeovers etc. This person may also be responsible for writing press releases etc or this may be a seperate role.
4) Political Media Advisers - A person who works (generally) for a politician providing advise on how to deal with the media on issues that arise. Would need quite a bit of media experience I expect.
5) Advertising Copywriters - Copywriting is basically writing text or "copy" (nothing to do with the other use of the term which refers to stopping people copying your work!). A copywriter has to be a good writer, someone who can get their message across well, in a way that will get people's attention or challenge them etc. Will need very good grammar as well as some editing skills. Specifically advertising copywriter writes the text for printed or web based advertising.
6) Community Relations Managers. Generally organisations that don't have to market themselves a lot but do have to keep a strong community profile so they are seen as a "good guy" rather than a "bad guy" employ these. Example might be a paper mill or coal mine who employ this person to manage all the community activities and sponsorships etc they get involved in to be seen as a "good corporate citizen"
7) Media Researchers - I'm fairly certain this is someone who will work in researching the news for information about a particularly company, person or industry. Large companies and politicians like to know what is being said about them and their competitors so they can react appropriately.
8) Marketing Communication Specialists - This one can mean a lot of different things depending on the company. Basically it's someone working in a marketing role - they could be doing anything from developing marketing campaigns, writing copy, liasing with advertising agencies, a whole lot of things. The smaller the company the more different roles they will end up doing!
Wow I didn't mean to write this much but hope it helps! I probably couldn't be a copywriter, i'm too wordy!
Best of luck
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