Andrew Tuma, I agree. WE should have a glossary or something somewhere. I'll try to address the specific points you mention. I might go into a little more detail then warranted, but hopefully it will help set some context.
Generally, you are right. There is a little bit of inconsistency in naming between E9 and E10. The biggest place this bubbles up is in documentation on topliners.
- Picklist vs. Select List - these terms are used pretty much interchangeably
- Companies vs. Accounts - This really depends on which system you are talking about. In Eloqua, the terms are pretty interchangeable. For example, the "entity" in Eloqua is called an "Account", but the name of the entity that links it on the contact is called the "company". However, CRM's use different terms. The majority refer to that entity as an "account", but company isn't unheard of.
- Microsite vs. Hypersite - IN E9 a "microsite" and a "hypersite" are different things. A microsite is basically a static landing page or group of landing pages, where a hypersite can be personalized. It got a little confusing. So, the concept was merged in E10. So, now they are mostly refered to as "microsites". There is a little legacy usage of the word "hypersite", mostly in the initial default one that is created. It's called "your first hypersite"
- Ah "data cards" vs. "Custom objects". This can be a little confusing, so bear with me. There is an entity in Eloqua, that can be used to store a many to one relationship with contacts (or accounts). That entity is colloquially referred to as "data cards". There are 3 types of data cards, which all have different levels of functionality tied to them. "Custom Objects", "Events" and "Surveys". If you do not have a specific reason to use a particular one, I would recommend "Custom Objects". Old timers, like me tend to refer to them as "data cards". Feel free to correct me if I say it.